Apparatus and method for cutting glass

ABSTRACT

A method of scoring glass at a selected distance from the end of an advancing ribbon of glass which comprises poising scoring means in proximity to the ribbon, moving the ribbon past the scoring means and measuring the length of glass which passes the scoring means, accelerating the scoring means parallel to the moving ribbon and out of contact with it until its speed is slightly less than that of the ribbon as the end of the selected length approaches the scoring means, attaching the moving ribbon and scoring means together as the end of the length to be cut reaches the scoring means whereby they move in unison, activating the scoring means, disengaging the scoring means, and returning it to its original position.

United States Patent [191 Halberschmidt et al.

Josef Audi, Aachen, both of Germany [73] Saint-Gobain,Neuilly-sur-Seine,

France Filed: Mar. 21, 1972 Appl. No.: 236,601

Assignee:

[30] Foreign Application Priority Data Mar. 22, 1971 France 7109942References Cited UNITED STATES PATENTS 3/1963 Harris 83/319 X 4/1970Wehr 83/319 X [451 Jan. 15, 1974 3,169,429 2/1965 Bognar 83/319 X1,729,582 9/1929 Kast 3,164,046 1/1965 Arnaud 3,377,900 4/1968 Baker3,566,728 3/1971 Ohmasu..... 3,656,385 4/1972 Kimball 83/294 X PrimaryExaminer-Frank T. Yost Attorney-Willis H. Taylor, Jr. et al.

[57] ABSTRACT A method of scoring glass at a selected distance from theend of an advancing ribbon of glass which comprises poising scoringmeans in proximity to the ribbon, moving the ribbon past the scoringmeans and measuring the length of glass which passes the scoring means,accelerating the scoring means parallel to the moving ribbon and out ofcontact with it until its speed is slightly less than that of the ribbonas the end of the selected length approaches the scoring means,attaching the moving ribbon and scoring means together as the end of thelength to be cut reaches the scoring means whereby they move in unison,activating the scoring means, disengaging the scoring means, andreturning it to its original position.

3 Claims, 5 Drawing Figures PATENIEDJWEW 3.785.229

SHEET 2 0F 4 Fig. 2

1 APPARATUS AND METHOD FOR CUTTING GLASS This invention relates to theconstruction and operation of a machine for transversely cutting a glassribbon in movement in which the length of glass to be severed from itsadvancing end is registered in a measuring instrument and in which acutting bridge is mounted for movement over and parallel to the ribbonand is coupled to the ribbon so as to move with it during the scoring ofthe glass, the score being traced while the bridge and ribbon aretraveling at the same speed. The bridge is uncoupled from the ribbonafter the scoring and re turned to its upstream position ready for thenext operation.

In known apparatus of this type the cutting bridge stands in itsupstream position until the length of glass to be severed has passed,and at that moment the bridge is coupled to the ribbon by direct contactwith the ribbon. In that technique the bridge is accelerated to ribbonspeed in a very short time and, because of the mass of the bridge,generates problems of some magnitude. The braking force exerted on theribbon by the bridge reduces the output of the apparatus and causesdifferences in the lengths cut off. Such imperfections were tolerablewith apparatus of the speeds of production of standard apparatus. Butwith increase in rates of production such irregularities are notacceptable.

It is an object of the invention to provide a process of severance whichremoves the difficulties inherent in such prior art methods. Anotherobject is to provide efficient apparatus for scoring glass ribbon andwhich is quick in operation, reduces braking effect to a minimum,increases output, and improves the quality of the product bysubstantially eliminating the forces which previously acted on theribbon at the moment of coupling the bridge thereto.

These objects are accomplished, generally speaking, by accelerating thebridge out of contact with the ribbon until it is at a speed onlyslightly less than that of the ribbon before the scoring elementcoincides with the imaginary cutting line marking the inner end of thepiece which is to be severed, coupling the ribbon and bridge together asthey coincide so that bridge and ribbon are locked together at the samespeed, making the score, and freeing the bridge from the ribbon for itsreturn trip.

In this way the forces necessary to acceleration are devoid ofunfavorable action on the glass ribbon and the measurement of the lastportion of the length of the glass which is to be cut off is carried outwith a relative speed between the bridge and the glass which is verysmall. The last part of the measurement is made with great precision indistinction from prior practice. Furthermore the coupling, properlyso-called, of the bridge to the glass ribbon involves only very smallforces of acceleration so that precision on the length of the cut is notcompromised and that the ribbon does not receive the damage whichsometimes accompanied the coupling with prior methods and apparatus.

In accordance with the invention the cutting bridge is accelerated to aspeed only a little less than the speed of the glass ribbon, moving, upto the instant of coupling, with a very small difference in speed.

According to another feature of the invention the acceleration of thecutting bridge from its upstream position of rest is initiated by asignal which is supplied by the same measuring apparatus which is usedto measure the length of ribbon to be cut off. i

The process according to the invention may be carried out in differentways. An apparatus which is convenient in practice is essentiallycharacterized by the fact that the cutting bridge is provided withinternal apparatus which moves it downstream and that the cutting bridgecarries a measuring apparatus which measures the length of the glasssheet to be cut off and contains, in addition to an apparatus generatinga signal at the moment when the exact length to be cut off has beenreached, a second apparatus generating a signal at a predeterminedinstant of time prior to that signal which announces the coincidence ofthe cutting line and the scoring instrument, this latter signal beingused to start the bridge from rest and to accelerate it to a speedapproaching that of the glass ribbon. The apparatus for accelerating thebridge is advantageously coupled to the mechanism which drives the glassribbon, through a gear train having a ratio of transmission less than 1.One is thus assured in a simple way that the bridge, after itspre-acceleration, will always be found within the same ratio of speedsregardless of the absolute speed of displacement of the ribbon.

According to another characteristic of the invention the apparatusincludes in the gear train connected to the drive for the glass ribbon,a clutch which automatically disengages the bridge from its acceleratingmechanism at the instsnt when the bridge is coupled to the ribbon.

In the preferred form of apparatus illustrated in the drawings thecutting bridge is attached directly to the moving ribbon of glass bymeans of a friction plate carried by the bridge, and which can be raisedand lowered into and out of contact with the moving ribbon.

The above and further objects and novel features of the presentinvention will more fully appear from the following detailed descriptionwhen the same is read in connection with the accompanying; drawings. Itis to be expressly understood however, that the drawings are for thepurpose of illustration only and are not intended as a definition of thelimits of the invention.

In the drawings wherein like reference charactes refer to like partsthroughout the several views:

FIG. 1 is a diagrammatic side view of the essential parts of a cuttingmachine according to the invention;

FIG. 2 is a diagrammatic end view, partly in section, of the samemachine as viewed from its downstream end;

FIG. 3 is a view corresponding generally to FIG. 2 but showing aconstruction wherein the mechanical connections between shafts 4 and 28are replaced by electrical telemetric connections;

FIG. 4 is a diagram of one form which the telemetric connections mayhave; and

FIG. 5 is a diagram of a modified form of such connections.

The glass ribbon 1 after having been continuously formed and cooled insome known way, is carried on rollers 2, 3 in the direction of the arrowF, called downstream. The rollers 2 are driven through a shaft 4 androllers 3 are driven by shaft 4a from some usual source of power notshwon. Details of the construction of such drives are obvious and arenot illustrated. These rollers are driven at the same peripheral speedby linkage through the same gear box 5.

A pair of rails 8 extend along the opposite sides of the course of theglass ribbon and a cutting bridge 6 is mounted for translatory movementalong them by rollers 7. At each end, the cutting bridge is connected bya belaying cleat 9 to chains 10, which are connected through sprocketwheels 11 to chains 12, which are in turn connected to a transmission32, 31, 30, 29 which provides for the acceleration of the bridge fromstart to a speed approaching that of the glass, and for its return afterthe cut is made. The cutter 15 which scores the glass is supported byand slides along the bridge 6. This cutter is operated in the usual way,being thrust against the glass by the usual signal and lifted when thescore has been made.

In this invention major attention is directed toward the problem ofcoupling the bridge to the moving glass, to achieve which the bridgesupports a plate 18 of large surface area, just above and out of contactwith the glass. The supports for the plate include two rods 20 which areattached to the plate, extend upward through the bridge, and areattached to the pistons in cylinders 19, which are operatedpneumatically upon receipt of a signal, to raise or lower the rods andthe plate, from and into contact with the moving ribbon of glass. Theplate has a non-abrasive friction surface attached to its lower face,for instance a rubber pad with an intaglio surface pattern comosed ofchannels open to the air to prevent any suctional adherence to the glassat the moment of release.

The cutting bridge also carries a measuring wheel 22 which rolls on theglass at all times and is directly connected to an impulse generator 23which emits electrical impulses corresponding to the passage of measuredlengths of the glass. These impulses are sent to a counting unit 24provided with a pre-selector which, at the moment when the impulses fromthe impulse generator match the length of glass selected for cutting asset in the pre-selector, starts the operation of the bridge.

The motion of the bridge downstream is provided for by drive shaft 4 ofthe rollers 2, which is connected by right angle gears in box 25 toshaft 26, which is connected through gear box 27, FIG. 2, and shaft 28,to a gear 29 which meshes with a gear 30, which drives shaft 31, andthrough chains 12 and sprockets 32 and 11, drives chains 10 which areconnected to the ends by the bridge by couplings 9. This transmission ispreferably constructed to provide a speed downstream of 90 to 95 percentof the speed of the glass ribbon.

In the power train between the gear box 27 and the gear 29 is anelectrically operated clutch 33 and an overrunning clutch 34 whichreleases the gear 29 from the shaft 28 as soon as the speed of thebridge exceeds the 90 to 95 percent provided by the transmission, thatis to say, as soon as the bridge is attached to and traveling at thespeed of the glass.

On the other side of the gear 29 the shaft 28 carries the electric motor36, the brake 35, and the electrically operated clutch 37, the functionof which is to return the bridge to its upstream position after the cutor score is made.

The machine operates thus. The operation is started by setting thecounter-preselector to the length of glass to be cut from the end of theadvancing ribbon, at the same time registering in the same unit a length6 to 10 cm., e.g., less than the said length. When the shorter length isreached by the roller 22 the counter emits a first signal which engagesclutch 33 and drives chains 12 and 10 through gears 29, 30 and shaft 31,which start the cutting bridge and accelerate it to a speed slightlyless than that of the glass. The measuring roller 22 is now turning at amuch reduced speed which continues until a moment when, the exact lengthhaving been measured, a second signal activates the cylinders 19 andlowers the plate 18 onto the glass, equalizing the speed of glass andbridge. The bridge now moves at the speed of the glass, which isslightly superior to the speed produced by the transmission anddisengages the clutch 33, thus disconnecting the drive. The scribe 15 isnow activated and scores the glass at the preselected length. When thescoring is finished the bridge is freed from the glass by raising theplate 18 and the bridge is stopped by disengaging clutch 33. The clutch37 is then engaged and returns the bridge to its starting position, themotor 36 is de-energized and braked. The clutch 37 is againdisconnected, and the motor starts again, putting the apparatus incondition for another cycle. During the return of the bridge to startingposition the counting mechanism is again measuring the ribbon passingbeneath it and initiates the new cycle as soon as the selected length ofribbon has passed beneath it. It will be observed that the gears 29, 30are driven by rollers 2 or by the same source of power that drivesrollers 2 and 3, during the first part of the cycle, and in onedirection, and that during the second part of the cycle they are drivenin the opposite direction by the motor 36.

The impulse generators may be of different kinds, for instance aphotoelectric cell controlled by a gear mounted to turn with wheel 22.The preselector computers are usually electronic, for example any one ofseveral binary models for sale on the market, but an ordinary decimalmechanical counter is also useful. Supposing that the length of glass tobe cut off is 3,137 mm., this figure is imposed on the counter accordingto its nature or even is carried out manually; thereafter each impulseconstitues a unity, the counter itself generating the impulse. In oneknown type, a AND circuit passes the impulse of the counter at 0.0000 mm(or if one wishes to account for slippage, at 0.0010 mm.) and thisexcites the command relay which controls elements l9 and 18. Thesecondary controls involve a second AND circuit which constitutes thepreselector and which releases the impulse of the counter when it marks,for instance, 0100 mm., exciting the relay which controls clutch 33. Thepreselector counter is diagrammed in FIG. 2 at 24 of the drawings, withcontrol lines for 0010 and 0100 mm. indicated.

We claim:

1. Apparatus for marking measured lengths along a continuously movingribbon supported on ribbon driving means, said apparatus comprising abridge spanning the ribbon, marking means in the bridge, railssupporting the bridge for reciprocating motion lengthwise of the ribbon,means arranged in the bridge and engaging the ribbon to measure relativemotion of the ribbon and bridge lengthwise of the ribbon, means to clampthe bridge to the ribbon, a drive train including a clutch, said drivetrain being coupled at one end to said driving means and being coupledat the other end to said bridge, said drive train imposing upon saidbridge when said clutch is engaged a speed less than that of saidribbon, means coupled to said measuring means to generate successivefirst and second signals upon measurement of first and second lengths bysaid measuring 3. Apparatus according to claim 2 further comprising amotor, a brake, and an additional clutch, said motor and brakeconnecting via said additional clutch into said drive train between saidoverrunning clutch and bridge, whereby upon disengagement of saidfirstnamed clutch and clamping means and upon engagement of saidadditional clutch the bridge may be decelerated by activation of saidbrake and may be restored upstream of said ribbon upon energization ofsaid motor.

1. Apparatus for marking measured lengths along a continuously movingribbon supported on ribbon driving means, said apparatus comprising abridge spanning the ribbon, marking means in the bridge, railssupporting the bridge for reciprocating motion lengthwise of the ribbon,means arranged in the bridge and engaging the ribbon to measure relativemotion of the ribbon and bridge lengthwise of the ribbon, means to clampthe bridge to the ribbon, a drive train including a clutch, said drivetrain being coupled at one end to said driving means and being coupledat the other end to said bridge, said drive train imposing upon saidbridge when said clutch is engaged a speed less than that of saidribbon, means coupled to said measuring means to generate successivefirst and second signals upon measurement of first and second lengths bysaid measuring means, means responsive to said first signal to engagesaid clutch, and means responsive to said second signal to engage saidclamping means, to activate said marking means, and to disengage saidclutch and clamping means, whereby said bridge can be stopped andreturned to its starting point.
 2. Apparatus according to claim 1further comprising an overrunning clutch in said drive train permitting,upon activation of said clamping means, entrainment of the bridge by theribbon at a higher speed than called for by said drive train. 3.Apparatus according to claim 2 further comprising a motor, a brake, andan additional clutch, said motor and brake connecting via saidAdditional clutch into said drive train between said overrunning clutchand bridge, whereby upon disengagement of said first-named clutch andclamping means and upon engagement of said additional clutch the bridgemay be decelerated by activation of said brake and may be restoredupstream of said ribbon upon energization of said motor.